I think the discussion isn't far from what you said. Interoperability is important, and UAX #29 must be the best one to improve it.
It was questioned since yesterday that how much the feature built by doing so is useful, and if it's a worth effort to improve it given the level of the feature it can do. Coincidentally I was thinking so too since I sent the last mail.
Certainly it shouldn't be dropped for backward compatibility. But improving--feature-wise or interoperability-wise--will involve costs to discuss, spec, and implement. If the feature by doing so will never suffice what authors need due to its nature, we may want to leave it as is.
Neither InDesign nor MS Word has the feature. XSL says "its use is not recommended"[1]. I don't think people would complain if we deprecate this value, although, I have no idea if CSS has a system to deprecate existing features.
Regards,
Koji
[1] http://www.w3.org/TR/xsl11/#text-transform
-----Original Message-----
From: fantasai [mailto:fantasai.lists@inkedblade.net]
Sent: Wednesday, February 23, 2011 10:40 AM
To: Koji Ishii
Cc: Brady Duga; Asmus Freytag; Mark Davis ☕; Xaxio Brandish; John Cowan; Christoph Päper; W3C style mailing list; www-international@w3.org; Bert Bos; Håkon Wium Lie
Subject: Re: [css3-text] text-transform:capitalize
On 02/21/2011 10:49 PM, Koji Ishii wrote:
> Thank you all for the great contributions, it looks like we're in the consensus for the following points:
>
> 1. The feature should rely on Unicode to define its scope 2. The name
> of the value should stay unchanged 3. The wording "language-specific
> rules *must* be used"[1] should be weakened
> at least for this value as language-specific rules for this value is more
> complicated than upper/lower. We'd like to allow UAs to implement
> language-specific rules, but we might not be able to test and make them
> interoperable.
> 4. Use UAX#29 for word break
> 5. Apply Titlecase_Mapping defined in Unicode[2] to the first letter
> of every word
I'd like to add a couple clarifications to what we're discussing here.
1. The 'capitalize' value exists since CSS1. [1] It's value name absolutely
cannot be changed, neither can it be dropped from the spec.
2. The spec uses the term titlecase because it intends to use the titlecase
character mappings from Unicode. As several people have pointed out,
using the uppercase tables would not give correct results for two-letter
characters like dz.
3. Similarly, the requirement for language-specific rules is for the case-mapping
rules, not for the word-boundary rules.
The issue here is the word-boundary and word-selection rules, which vary by language and indeed vary within language (sometimes depending on usage of the phrase, not even on the orthographic variant). Bert and Håkon may correct me if I'm wrong, but I believe the original intention was for the 'capitalize'
value to be very simple and not depend on context or language. The original spec text, "first character of each word" is not correct even for English, and I am sure they were aware of this when they wrote it. Punctuation complicates the situation: one cannot rely only on space-detection to capitalize words.
For that reason we may want to rely on UAX#29 to achieve interoperability.
But I think to expect UAs to do anything more intelligent than that is asking too much.
[1] http://www.w3.org/TR/CSS1/#text-transform
~fantasai